The present invention relates to an LCD (Liquid Crystal Display) for displaying images including texts and graphics and, more particularly, to a method of producing and driving an LCD which is easy to produce and has a desirable viewing angle characteristic.
In a TN (Twisted Nematic) type LCD extensively used today, while a voltage is not applied, LC molecules are parallel to the surfaces of substrates and render "white". On the application of a voltage, the molecules change their director in the direction of an electric field. As a result, sequential transition occurs from the "white" state to a "black" state. However, the viewing angle available with the conventional LCD is limited due to the behavior of the molecules occurring in response to the voltage. The limited viewing angle is particularly noticeable in the rising direction of LC molecules in the event of halftone display.
Implementations for improving the viewing angle are taught in, e.g., Japanese Patent Laid-Open Publication Nos. 63-106624 (Prior Art 1 hereinafter) and 6-43461 (Prior Art 2 hereinafter). The problem with Prior Art 1 is that it is not practicable without resorting to a photoresist step and a plurality of rubbing steps not necessary for the production of ordinary TN type LCDs. Prior Art 2 needs various kinds of microtreatment including a photoresist step for a common electrode and not necessary for the production of ordinary TN type LCDs. Further, the two substrates must be put together by a highly advanced technology. Moreover, when a voltage is applied to an electrode, it is likely that a sufficient electric field does not act in a certain portion, preventing the LC from sufficiently responding to the applied voltage. This lowers contrast available with the LCD.